1) Field of the Invention
The present invention relates generally to cotton harvesters and, more specifically, to an adjustable doffer column structure for a cotton picker row unit.
2) Related Art
Cotton harvesters of the spindle type such as the John Deere model 9960 Cotton Picker include row units with upright picker drums having spindle bars defining rows of picking spindles. Adjacent each of the picker drums is a doffer column with a plurality of doffer pads supported on a shaft for rotation directly above the rows of spindles to unwrap cotton from the spindles and direct the cotton towards conveying structure on the row unit. For efficient doffing, the vertical position of doffer column must be carefully adjusted relative to the picker drum. If the doffer pads are too close to the spindles, the doffer pads wear quickly and pieces of the pad break off to cause specking of the cotton. Improper adjustment can also put added stress on the spindles and spindle bearings. Therefore, the doffer columns must be adjusted periodically to optimize productivity.
Conventional doffer column adjustment structure includes a doffer adjuster having a threaded adjusting screw with a locking nut located near the top of the row unit housing. To adjust a doffer column, the locking nut is first loosened with a wrench. A second wrench is used to turn the adjusting screw to adjust the vertical position of the column. When the doffer column is in the desired position, the adjusting screw is held with one wrench while the locking nut is tightened with the other wrench. The adjusting procedure can be somewhat awkward and time-consuming. Often, the operator uses one hand to sense the adjustment of the pads relative to the rows of spindles, which can be difficult
Various devices, an example of which is shown in U.S. Pat. No. 4,819,415, provide automatic doffer column adjustment. However, most automatic devices are relatively complicated and expensive and are not always reliable.